As the thermal stabilizer of PVC processing, being the combination null halogen content polymer of organic

摘要

PROBLEM TO BE SOLVED: To obtain a heat stabilizer which, when added to a PVC composition, prevents the composition form undergoing zinc scorch during processing the composition at a high temperature by combining a specified zinc mercapto ester with an organic thio compound, etc.;SOLUTION: This stabilizer contains an organic thio compound; a zinc mercapto ester; 0 to about 20 wt.% basic alkali (alkaline earth) metal compound; and 0 to about 10 wt.% substituted dihydropyridine. The organic thio compound is exemplified by a mercaptan, dithiodiglycol, or dithiodiglycol polyformal. The zinc mercapto ester used is exemplified by a zinc mercapto acid ester represented by the formula: Zn-[S(CH2)x-C(=O)OR]2 (R is a hydrocarbyl group having 2 to about 22 carbon atoms; and x is 1 or 2) or a zinc mercaptoalkylcarboxylic acid ester represented by the formula: Zn[SCH2(CH2)qO- C(C=O)R5]2 (R5 is a 1-18C alkenyl or alkyl or a 6-12C aryl; and q is 1-6).;COPYRIGHT: (C)2000,JPO